The Ape Who Guards the Balance — Elizabeth Peters

The prospects for the 1907 archaeological season in Egypt seem fairly dull to Amelia. As a result of Emerson's less-than-diplomatic behaviour they have been demoted to examining only the most boring tombs in the Valley of the Kings - mere leftovers, really. And then, in a seedy section of Cairo, the younger members of the Peabody-Emerson clan purchase a mintcondition papyrus of the famed Book of the Dead, and so begins a new adventure into antiquity.

Suddenly, the season for Amelia changes from dull to deadly as she has to untangle a web woven of criminals and cults, stolen treasures and fallen women - all the while under the unblinking eye of a ruthless, remorseless killer.